John Pohlman, PhD
John Pohlman is a Research Chemist with the Woods Hole Coastal and Marine Science Center Gas Hydrates Project.
Science and Products
Filter Total Items: 62
The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin
Analytical challenges in obtaining high quality measurements of rare earth elements (REEs) from small pore fluid volumes have limited the application of REEs as deep fluid geochemical tracers. Using a recently developed analytical technique, we analyzed REEs from pore fluids collected from Sites U1325 and U1329, drilled on the northern Cascadia margin during the Integrated Ocean Drilling...
Authors
Ji-Hoon Kim, Marta E. Torres, Brian A. Haley, Miriam Kastner, John W. Pohlman, Michael Riedel, Young-Joo Lee
Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans
Marine sediments contain about 500–10,000 Gt of methane carbon1, 2, 3, primarily in gas hydrate. This reservoir is comparable in size to the amount of organic carbon in land biota, terrestrial soils, the atmosphere and sea water combined1, 4, but it releases relatively little methane to the ocean and atmosphere5. Sedimentary microbes convert most of the dissolved methane to carbon...
Authors
John W. Pohlman, William F. Waite, James E. Bauer, Christopher L. Osburn, N. Ross Chapman
The biogeochemistry of anchialine caves: Progress and possibilities The biogeochemistry of anchialine caves: Progress and possibilities
Recent investigations of anchialine caves and sinkholes have identified complex food webs dependent on detrital and, in some cases, chemosynthetically produced organic matter. Chemosynthetic microbes in anchialine systems obtain energy from reduced compounds produced during organic matter degradation (e.g., sulfide, ammonium, and methane), similar to what occurs in deep ocean cold seeps...
Authors
John W. Pohlman
Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep
Delineating sediment organic matter origins and sediment accumulation rates at gas hydratebearing and hydrocarbon seeps is complicated by the microbial transfer of 13C-depleted and 14Cdepleted methane carbon into sedimentary pools. Sediment 13C and 14C measurements from four cores recovered at Bullseye vent on the northern Cascadia margin are used to identify methane carbon assimilation...
Authors
John W. Pohlman, Michael Riedel, Ivana Novosel, James E. Bauer, Elizabeth A. Canuel, Charles K. Paull, Richard B. Coffin, Kenneth S. Grabowski, David L. Knies, Roy D. Hyndman, George D. Spence
Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence
Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional...
Authors
Patrick E. Hart, John W. Pohlman, T.D. Lorenson, Brian D. Edwards
Observations of mass fractionation of noble gases in synthetic methane hydrate Observations of mass fractionation of noble gases in synthetic methane hydrate
As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings are presently dissociating and releasing methane and other gases to the oceanatmosphere system. A key challenge in assessing the susceptibility of gas hydrates to warming climate is the lack of a technique able to distinguish between methane recently released from gas hydrates and...
Authors
Andrew G. Hunt, John W. Pohlman, Laura A. Stern, Carolyn D. Ruppel, Richard J. Moscati, Gary P. Landis, John C. Pinkston
Science and Products
Filter Total Items: 62
The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin
Analytical challenges in obtaining high quality measurements of rare earth elements (REEs) from small pore fluid volumes have limited the application of REEs as deep fluid geochemical tracers. Using a recently developed analytical technique, we analyzed REEs from pore fluids collected from Sites U1325 and U1329, drilled on the northern Cascadia margin during the Integrated Ocean Drilling...
Authors
Ji-Hoon Kim, Marta E. Torres, Brian A. Haley, Miriam Kastner, John W. Pohlman, Michael Riedel, Young-Joo Lee
Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans
Marine sediments contain about 500–10,000 Gt of methane carbon1, 2, 3, primarily in gas hydrate. This reservoir is comparable in size to the amount of organic carbon in land biota, terrestrial soils, the atmosphere and sea water combined1, 4, but it releases relatively little methane to the ocean and atmosphere5. Sedimentary microbes convert most of the dissolved methane to carbon...
Authors
John W. Pohlman, William F. Waite, James E. Bauer, Christopher L. Osburn, N. Ross Chapman
The biogeochemistry of anchialine caves: Progress and possibilities The biogeochemistry of anchialine caves: Progress and possibilities
Recent investigations of anchialine caves and sinkholes have identified complex food webs dependent on detrital and, in some cases, chemosynthetically produced organic matter. Chemosynthetic microbes in anchialine systems obtain energy from reduced compounds produced during organic matter degradation (e.g., sulfide, ammonium, and methane), similar to what occurs in deep ocean cold seeps...
Authors
John W. Pohlman
Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep
Delineating sediment organic matter origins and sediment accumulation rates at gas hydratebearing and hydrocarbon seeps is complicated by the microbial transfer of 13C-depleted and 14Cdepleted methane carbon into sedimentary pools. Sediment 13C and 14C measurements from four cores recovered at Bullseye vent on the northern Cascadia margin are used to identify methane carbon assimilation...
Authors
John W. Pohlman, Michael Riedel, Ivana Novosel, James E. Bauer, Elizabeth A. Canuel, Charles K. Paull, Richard B. Coffin, Kenneth S. Grabowski, David L. Knies, Roy D. Hyndman, George D. Spence
Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence
Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional...
Authors
Patrick E. Hart, John W. Pohlman, T.D. Lorenson, Brian D. Edwards
Observations of mass fractionation of noble gases in synthetic methane hydrate Observations of mass fractionation of noble gases in synthetic methane hydrate
As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings are presently dissociating and releasing methane and other gases to the oceanatmosphere system. A key challenge in assessing the susceptibility of gas hydrates to warming climate is the lack of a technique able to distinguish between methane recently released from gas hydrates and...
Authors
Andrew G. Hunt, John W. Pohlman, Laura A. Stern, Carolyn D. Ruppel, Richard J. Moscati, Gary P. Landis, John C. Pinkston